According to PC Magazine, token passing is a method of passing messages between computers in a network. Token passing is used in a networks setup with either a ring or bus topography.
Networks using token passing keep a constant supply of the token frames running through the network. When a message is to be sent, a computer on the network places the destination address and as much of the message as possible in an empty token. The token then proceeds down the network, passing through each computer between the sender and the recipient. When the token reaches the destination address, it is emptied and the message is received. The empty token then proceeds around the network until needed again.